The present invention relates to a door status sensing device for a shipping or transport container, and more specifically, to a door status sensing device to monitor opened and closed positions of doors disposed in the container.
Existing transport containers that monitor door positions use extensive and complicated wire-based mechanical systems to determine door opened and closed positions. In these traditional mechanical door status sensing systems, the wires extend the entire length of the container. The long wires make the system more susceptible to failure, are often difficult to effectively replace, and create a need for higher electrical power to properly operate the system. The long wires can be subject to damage or interference, and add cost and reduce effectiveness of these systems. The long wires make the refrigeration system more susceptible to failure, potentially ruining temperature sensitive goods. In some instances, shipment of goods in containers that have long wires is avoided for these reasons.
These transport containers typically use mechanical door position sensing systems that wear out due to repeated operation. Worn mechanical door position sensors fail to indicate when a door is opened inappropriately. Over time, these systems become less reliable and the possibility of goods that are stolen or spoiled significantly increases.